Suction cup



FIG. 1 is a perspective view of the suction cup;

FIG. 2 is a front view of the suction cup;

FIG. 3 is a rear view of the suction cup;

FIG. 4 is a left side view of the suction cup (with the right side a mirror image thereof);

FIG. 5 is a top view of the suction cup; and,

FIG. 6 is a bottom view of the suction cup.

The broken lines depict unclaimed structure and form no part of the claimed design. 

CLAIM The ornamental design for a suction cup, as shown, and described. 